Having a persistant problem with fuel table codes 231,232 & 233. No vacuum leaks and intake vacuum reads normal. New O2 sensors no help. I dissabled the "Check Engine" light and it passed smog great here in SoCal with better numbers than two years ago! But the light came back on a few days later with the same codes. I've disconnected the battery for 15 min to make the ECU reset the table. Still no help. Engine starts and runs fine otherwise. Could they be caused by using 87 octane gas? Thanks...